Funding for this research was provided by:
National Natural Science Foundation of China (81771825)
Beijing Municipal Science and Technology Commission (D17110003017003)
Ministry of Science and Technology of China (2017YFC1307904)
Received: 21 December 2017
Accepted: 20 July 2018
First Online: 3 September 2018
Ethics approval and consent to participate
: The study protocol was approved by institutional review board of Tsinghua University School of Medicine and the written consent forms were obtained from all the subjects prior to the initiation of this study.
: Not applicable.
: The authors declare that they have no competing interests.
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